Claim Construction: Learning the Art


Introduction to Claims

A claim is portion of specification which fulfils a separate and distinct function. It and it alone defines monopoly; and the patentee is under a statutory obligation to state in the claims clearly and distinctly what is the invention which he desires to protect. The office of a claim is to define and limit with precision what it is which is claimed to have been invented and therefore patented.[1]

‘Claims’ define crux of the invention, which are provided in fresh page after detailed description of the invention.  Any aspect of the invention which s not claimed is said to be ‘disclaimed’ and is open to public for its usage. Also, it becomes very difficult for patentee to establish infringement on any third party on such grounds. It is further stated that the patentee’s duty is not to prevent all possible argument as to whether there is or is not infringement in particular case, but to enable the court to formulate the questions of fact to be answered.

Trade Related Aspects of Intellectual Property Rights (TRIPS) agreement obligates its members (member countries) to include a mandatory requirement that an applicant for a patent in their jurisdiction should provide a disclosure that enables a person skilled in the art to practice the invention. However TRIPS agreement makes it optional for its members to seek disclosure of best mode from patent applicants in their jurisdiction.

Article 29 of the TRIPS agreement deals with the enablement requirement and disclosure of best mode.

Practically, in a patent application, the claims are usually worded in broader perspective keeping all the possible infringer in mind. However, such over broad claims may not always be supported by sufficient description. Hence Claims in a specification should always be backed by sufficient experimental data.

The duty of a patentee is to formulate his claim in such a way as to define with clarity the area of his monopoly; the claim is the solemn operative part of the specification in which the patentee sets himself to achieve that purpose.[2]

A patentee must mark out with adequate distinctiveness the boundary of the territory that he claims to be exclusively his own.[3]

The claim is usually drafted in a number of paragraphs serially numbered. The first claim which is made is as wide as possible.

The subsidiary claims refer to the main claim and include qualifying or explanatory clause on the various integers of the main claim or optional features. They may also contain independent claims. Although the claim clauses consist of a number of claims, the totality of the claims must relate to one invention only.

Claim Construction

It should be remembered that a claim is a statement of technical facts expressed in legal terms defining the scope of the invention sought to be protected.

A specification containing two independent claims shall not be allowed. To allow such a specification would be against the public interest and its effect would be to sacrifice clarity, succinctness, which are required by the act and to condone avoidable security and ambiguity.[4]

A claim could be limited by intended purpose and reference may be made to the body of the specification in the claim. Section 10(5) of the Indian Patents Act 1970 confines claim to a single invention or a group of inventions linked in so as to form a single inventive concept but this must be read so as to be consistent with Section 10(7) which enables an applicant to include claim in respect of “developments of, or addition to, the invention, that is the invention of the complete specification subject of Section 10(4), if they are developments or additions for which he could make a separate application under Section 6. Section 10(4) of the Indian Patents Act 1970 requires disclosure of best mode of carrying out the invention, as contemplated by the investor(s).

General Guidelines for construction of claims for patents

  1. The claims should define clearly and with precision the monopoly claimed so that the others may know the exact boundaries of the area within which they will be trespassers.
  2. The claims should prima facie provide the boundary of protection from the Patent alone.
  3. The court can receive evidence as to the meaning of technical terms in the claims, but the eventual ascertainment of the boundary of claims remains a task for the court alone.
  4. A claim must be given a purposive construction.
  5. The Court is entitled to distinguish between the essential and unessential features of an invention as claimed and to regard the scope of protection.
  6. The Court will not artificially strain the construction of a claim so as to include in the scope of protection a variant which has a material effect on the working of a patented invention.
  7. The mere fact that the defendant’s product or process represents an improvement does not necessarily enable infringement to be avoided.
  8. A Claim will not be capable of including a variant which itself of obviously equivalent function to the claimed feature at the date of publication of the patent.[5]
  9. The court will not extend the scope of a feature or features where the patentee has committed himself to the exclusion of variants.[6]

 Enablement/Sufficiency of Disclosure in Specification                                                          The patent specification provides a written description of the invention and the manner and process of making and using it. It includes the field and background of the invention, the drawings, detailed description of the invention, preferred embodiments, best mode of practising the invention and the patent claims.

One of the requirements for the grant of a patent in all jurisdictions is that the disclosure in the patent (usually, the specification) must enable persons of ordinary skill in the art to practice the invention, i.e., make the invented device or successfully practice the disclosed method. Failure to enable is grounds for invalidating a patent. In European Patent Law lack of enablement is referred to as insufficiency.

The term ‘sufficiency of disclosure’ refers to adequacy of pertinent information to be provided in the specification to enable an average skilled person to perform the invention. It is stated in Halsbury’s Law that insufficiency of description has two branches:
(1) complete specification must describe ‘an embodiment’ of the invention claimed in each of the claims and that the description must be sufficient to enable those in the industry concerned to carry it into effect ‘without their making further inventions’ and

(2) That the description must be fair i.e. it must be fair i.e. it must not be unnecessarily difficult to follow.[7]

The Complete Specification is a techno-legal document which fully and particularly describes the invention and discloses the best method of performing the invention. It is an extremely important document in the patent proceedings and hence it is advised that it should be drafted with utmost care without any ambiguity.

A complete specification must constitute the following aspects besides the title –

1) A full and particular description of the invention and its operation or use and the method by which it is to be performed;

2) A disclosure of the best method of performing the invention which is known to the applicant and for which he is entitled to claim protection.

3) A claim or claims defining the scope of invention for which the protection is sought. The Claim or claims should relate to one invention, whether the invention is for a process or for a product. It should be clear and succinct and be fairly based on the matter disclosed in the specification.

4) It should be accompanies by an abstract to provide technical information on the invention.

Section 10(4) of the Indian Patents Act, 1970, particularly deals with ‘contents of specification’, and lists out features to be covered in a complete specification. Drafting a complete patent specification in compliance with this section helps in overcoming the objections/ rejections raised by patent examiners during prosecution.

The complete specification should be drafted and submitted in Form 2 to the Indian Patent Office. It must be drafted in the following format:

1) Title;

2) Preamble of the invention;

3) Technical field;

4) Background of the invention;

5)) Objects of the invention;

6) Statement of the invention;

7) Brief description of drawings;

8) Detailed description of the invention;

9) Claims; and

10) Abstract

The complete specification must begin with an appropriate ‘Title’ which must not exceed 15 words. The title should not have any fancy language or abbreviation.

The Preamble of specification must state “The following specification particularly describes the invention and the manner in which it is to be performed. The preamble along with the title of the invention, address, and nationality of applicants should appear on the first page of Form 2.

The technical field section shall mention as to which field the invention belongs to. The background of the invention shall distinguish the invention with that which is being already practised. It shall discuss the teachings of the prior art and thereby mention the drawbacks or disadvantages for the same.

The objective of the invention is to bring about necessity of the invention. It is aimed at bringing about the solutions, advantages achieved by employing the invention at hand.

Statement of invention must cover all the independent claims put in the specification. It must be drafted in English and must have its own independent standing (not obvious as other claims).

The invention must be backed with brief drawings or graphical data that aid the understanding of the invention. Eg- Molecular diagram of a new type of sugar

A detailed description of invention must cover all the objectives of the invention at hand; it must be explained with help of drawings and experimental data. This detailed description must be such that a man of ordinary art- prudence is able to understand the characteristics- aesthetics of the invention.

Claims define the contours of rights, if and when a patent is granted for an invention. In a complete specification the description is followed by claims. Since, claims define the scope of legal protection, it is suggested that they should be drafted carefully to cover all the aspects of the protection being sought at the same time adequately distinguishing the prior art from the claimed invention.[8] Each claim is a separate invention and hence all the claims are not held invalid for one claim being invalid.

For Eg-            A Point ball pen comprising of:

a roller ball nib

a shock absorbing technology

a rubber coating on body of pen

An abstract is essentially summary of matter contained in a specification.[9] It should contain the title of invention and must not exceed more than 150 words.[10]It must contain the reference number accorded to the drawing in the specification.

A provisional patent application does not require claims, but it is a good practice if claims are provided in a provisional application. Incorporating claims in a provisional specification reduces the risk of losing priority during litigation or infringement proceedings. Provisional document acts as actual priority document that shall be referred along with complete specification by the courts at the time of infringement or litigation proceedings for establishing the facts of invention at the time of complete and Provisional stage.

In Press Metal Corporation Limited v. Noshir Sorabji Pochkhanwalla,[11] it was held that- It is the duty of a patentee to state clearly and distinctly the nature and limits of what he claims. If the language used by the patentee is obscure and ambiguous, no patent can be granted, and it is immaterial whether obscurity in the language is due to the design or carelessness or want of skill. In the above mentioned case the grant of patent was refused on the same ground of clam being written in obscure and ambiguous language.

** ( The Information relied upon in this Article are observations from P Narayanan’s Fourth Edition of Patent Laws)

[1] Lord Chelmsford in Harrison v. Anderston Foundry Co (1876) LR 1 App Cas 574

[2] Norton & Gregory Ltd. v Jacobs (1937) 54 RPC 271 at 276

[3] Clay v Alcock & Co Ltd. (1906) 23 RPC 745

[4] Beloit Corporation Appln [1974] RPC 478 at 483

[5] Heath v Unwin 2 WPC 296

[6] Furr v C.D. Truline [1985] FSR 553

[7] Halsbury, 3rd edn. Vol. 29p. 66 Para 138

[8] The Patent Manual,

[9] Rule 13(7)(b) of the Indian Patent Rules 2003

[10] Rule 13(7)(c),(d) of the Indian Patent Rules 2003

[11] 1982 PTC 259 (Bom)


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